Experiments were conducted under atmospheric pressures appropriate for Earth and Mars to determine the e,ciency of sand in saltation as a means for raising dust into the atmosphere under wind speeds which would otherwise be too low for dust entrainment. Experiments involving intimate mixtures of sand and dust (1:1 ratio by mass) showed that after an initial .urry of activity of a few seconds du...

Sand dunes have been observed throughout the surface of the planet Mars. Movement of these dunes has been theorized and inferred from the lack of craters on dunes. Dune movement has not yet been directly imaged, however. Understanding sand movement processes is vital to a correct Martian climate model, as well as the safety of future missions to Mars. Imagery from several Martian orbiters was a...

[1] Recent field observations demonstrate that a significant discrepancy exists between models and measurements of large dust aerosol particles at remote sites. We assess the fraction of this bias explained by assumptions involving four different dust production processes. These include dust source size distribution (constant or dynamically changing according to saltation and sandblasting theor...

Grain size distributions in eolian settings are the result of both sorting and abrasion of grains by saltation. The two are tightly coupled because mobility of particles determines abrasion rate, while abrasion affects the mobility of particles by changing their mass and shape; few field studies have examined this quantitatively. We measured grain size and shape over a 9 km transect downwind of...

Wind erosion from agricultural fields contributes to poor air quality within the Columbia Plateau of the United States. Erosion from fields managed in a conventional winter wheat– summer fallow rotation was monitored during the fallow period near Washtucna, WA, in 2003 and 2004. Loss of soil and PM10 (particulates ≤10 μm in diameter) was measured during six high wind events (sustained wind spee...

Sand dunes are found in a wide variety of shapes in deserts and coasts, and also on the planet Mars. The basic mechanisms of dune formation could be incorporated into a continuum saltation model, which successfully reproduced the shape of the barchan dunes and has been also applied to calculate interaction of barchans in a field. We have recently extended our dune model to investigate other dun...

AGGREGATE BEDFORMS AND YARDANGS AS SEEN BY THE HIRISE CAMERA N.T. Bridges, L.P. Keszthelyi, B.J. Thomson, J.J. Wray, M.E. Banks, R.A. Beyer, F.C. Chuang, K.E. Herkenhoff, K.E. Fishbaugh, A.S. McEwen, and T.I. Michaels; Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 ([email protected]); U.S. Geological Survey, Flagstaff, AZ 86001;A...